Intrinsic Conditions Research Articles

On a reaction–advection–diffusion equation with Robin and free boundary conditions

ABSTRACTA reaction–advection–diffusion equation with variable intrinsic growth rate, Robin and free boundary conditions is investigated in this paper. Firstly, we present a spreading–vanishing dichotomy for the asymptotic behavior of the solutions of the equation. Then, we obtain criteria for spreading and vanishing, and get an estimate for the asymptotic spreading speed of the spreading front. Moreover, numerical simulation is also given to illustrate the impact of the expansion capacity on the free boundary.

The effect of extrinsic cues on consumer perception: A study using milk tea products

Consumers’ acceptability may be affected by extrinsic factors as well as intrinsic sensory characteristics. The aims of this study were to determine the influence of extrinsic cues on consumers’ acceptance and flavor perception, to examine the discrimination ability of the check-all-that-apply (CATA) method for consumer evaluation, and to investigate possibility of using CATA for complex flavor products and many terms using commercial milk tea products as samples. A total of 240 consumers evaluated eight ready-to-drink milk tea samples in both intrinsic and extrinsic conditions. Participants rated overall liking, and liking and intensities of three dominant characteristics: sweetness, milk flavor, and black tea flavor, and selected attributes that they perceived among 93 CATA terms provided to them. Although extrinsic information on packaging positively influenced acceptability of liked samples, it did not change the preference for tasted samples. However, change in acceptability in the extrinsic evaluation differed between consumers who had previously consumed the particular product and those who had not. Correspondence analysis indicated that the intrinsic and extrinsic evaluations resulted in similar sample and term configurations. Consumers were able to use a large number of terms and distinguished among complex flavor samples using CATA method and intensity differences were shown with varying level of frequency. Reduction of terms was also possible based on the frequency data obtained from consumer evaluation using CATA method. Thus CATA evaluation could be considered for various food categories that sensory terms have not been developed previously.

Creencias pedagógicas respecto de las dificultades específicas del aprendizaje de las matemáticas desde la perspectiva de las educadoras diferenciales en una escuela pública de Chile

La presente investigación tiene como objetivo describir las creencias pedagógicas de las personas educadoras diferenciales sobre las dificultades específicas del aprendizaje en matemáticas. Este estudio presenta un diseño cualitativo con enfoque etnográfico, en el que participaron cuatro docentes de educación especial y se emplearon como instrumentos de recolección de información la entrevista en profundidad y la observación participante. Como técnica de análisis del corpus discursivo obtenido, se utilizó el análisis cualitativo de contenido. Entre los hallazgos más relevantes se encuentran: las dificultades específicas del aprendizaje de las matemáticas corresponden a una condición intrinseca al estudiantado, que el origen de estas dificultades está asociada tanto a un problema de salud, como a metodologías inadecuadas de enseñanza de las matemáticas. Así mismo, se propone que estudiantes que poseen estas dificultades tienen un problema a nivel del razonamiento matemático, el que les impide progresar en el aprendizaje de esta asignatura escolar.

Growth of mesophilic Aeromonas salmonicida in an experimental model of nigiri sushi during cold storage

The genus Aeromonas includes human pathogenic bacteria frequently isolated from seafood, and the increased consumption of ready-to-eat seafood poses new food safety issues regarding the presence of potentially pathogenic Aeromonas spp. in stored products for raw consumption, such as retail sushi with a shelf life of up to three days. This study assessed 1) the growth kinetics of a mesophilic A. salmonicida strain during storage at 4 °C and 8 °C in a nigiri sushi model, and 2) the strain variability in growth at pH ranging from 3.5 to 10 for a subset of mesophilic Aeromonas strains previously isolated from sushi.Inoculated slices of raw salmon were compared with and without rice. A predictive model for A. hydrophila (ComBase Predictor) did not sufficiently predict growth of the tested strain under the intrinsic conditions of nigiri sushi or salmon at both temperatures. Refrigeration alone (4 °C) did not inhibit growth of A. salmonicida on salmon. Within the first 72 h, representing the typical shelf life of retail sushi products, we observed a 10-fold increase in the concentration of the inoculated strain (including a lag-phase of approximately 34 h). Contact with acidified rice, resulting in a pH drop in the salmon, was the reason for the decreased bacterial viability in the nigiri sushi samples. However, the effect of acidification decreased at 8 °C, resulting in a 2-fold increase in the growth rate and a reduced lag-phase compared to refrigeration.Variability in the ability to grow in different pH levels was observed between strains. The highest color formation rates, representing cellular respiration analyzed in a phenotypic microarray system, were observed between pH 5 and 8. A few strains, including the A. salmonicida strain applied in the nigiri sushi model, were able to grow at pH 4.5 (at optimal temperature).The results demonstrated that mesophilic Aeromonas spp. can represent a microbiological hazard in retail sushi products during cold storage. Rice acidification in combination with low storage temperature (≤4 °C) are prerequisites to prevent growth of potentially pathogenic Aeromonas species during the relatively short shelf life.

Tackling membrane fouling in microalgae filtration using nylon 6,6 nanofiber membrane

Microalgae technology, if managed properly, has promising roles in solving food-water-energy nexus. The Achilles' heel is, however, to lower the costs associated with cultivation and harvesting. As a favorable technique, application of membrane process is strongly limited by membrane fouling. This study evaluates performance of nylon 6,6 nanofiber membrane (NFM) to a conventional polyvinylidene fluoride phase inverted membrane (PVDF PIM) for filtration of Chlorella vulgaris. Results show that nylon 6,6 NFM is superhydrophilic, has higher size of pore opening (0.22 vs 0.18 μm) and higher surface pore density (23 vs 18 pores/μm2) leading to higher permeance (1018 vs 493 L/m2hbar) and better fouling resistant. Such advantages help to outperform the filterability of PVDF PIM by showing much higher steady-state permeance (286 vs 120 L/m2hbar), with comparable biomass retention. In addition, unlike for PVDF PIM, imposing longer relaxation cycles further enhances the performance of the NFM (i.e., 178 L/m2hbar for 0.5 min and 236 L/m2hbar for 5 min). Overall findings confirm the advantages of nylon 6,6 NFM over the PVDF PIM. Such advantages can help to reduce required membrane area and specific aeration demand by enabling higher flux and lowering aeration rate. Nevertheless, developments of nylon 6,6 NFM material with respect to its intrinsic properties, mechanical strength and operational conditions of the panel can still be explored to enhance its competitiveness as a promising fouling resistant membrane material for microalgae filtration.

Increase in pea productivity associated with irrigation management

ABSTRACT Proper irrigation management is crucial to obtain high yields of pea, since its cultivation is recommended in cold and dry seasons. Taking into account the great genetic diversity, we considered necessary to evaluate cultivars which best adapt to the intrinsic conditions of Cerrado Region, as it presents low fertility soil, long dry period in the winter, drought periods (veranicos) in rainy season, mainly in January and February (summer). Thus, the aim of this study was to evaluate adaptability of green-pea cultivars under different irrigation depths in Northeast Region of state of Mato Grosso do Sul. The experiment was installed in a split plot scheme, with four irrigation depths [50, 75, 100 and 125% of crop evapotranspiration (ETc)] and at subplots, four pea cultivars (Forró, Frevo, Pagode and Samba) in a randomized block design with three replications. Pod length, number and mass of grains per pod, number of pods per plant, plant length, productivity and efficiency of water use were evaluated. Excess water supply (water stress) or shortage (water deficit) can cause decrease in the productivity of pea crop for green grains, considering replacement of 114.81% of Etc, the most recommended for the crop. Cultivar Forró, showed the best productive performance in relation to other cultivars, in the climatic conditions of Southern Cerrado (Mato Grosso do Sul, Brazil).

The intrinsic theory of linearly elastic plates

In an intrinsic approach to a problem in elasticity, the only unknown is a tensor field representing an appropriate ‘measure of strain’, instead of the displacement vector field in the classical approach. The objective of this paper is to study the displacement traction problem in the special case where the elastic body is a linearly elastic plate of constant thickness, clamped over a portion of its lateral face. In this respect, we first explicitly compute the intrinsic three-dimensional boundary condition of place in terms of the Cartesian components of the linearized strain tensor field, thus avoiding the recourse to covariant components in curvilinear coordinates and providing an interesting example of actual computation of an intrinsic boundary condition of place in three-dimensional elasticity. Second, we perform a rigorous asymptotic analysis of the three-dimensional equations as the thickness of the plate, considered as a parameter, approaches zero. As a result, we identify the intrinsic two-dimensional equations of a linearly elastic plate modelled by the Kirchhoff–Love theory, with the linearized change of metric and change of curvature tensor fields of the middle surface of the plate as the new unknowns, instead of the displacement field of the middle surface in the classical approach.

The influence of dynamic environmental conditions on capillary water uptake of building materials

Water capillary absorption is one of the main water uptake mechanisms in building materials, affecting their overall durability. Thus, the investigation of their capillary rise kinetics can be very useful as regards understanding buildings behavior, contributing to the increase of their durability and their service life. For this reason, a first-order mathematical model was used describing the capillary water uptake under dynamic environmental conditions (different air velocity, air temperature, and relative air humidity) for various natural and artificial building materials. This model successfully fits the experimental data. From the results, it was found that both building materials’ intrinsic characteristics and environmental conditions influence the capillary rise kinetics. In order to assess the validity of the proposed model, a comparison with a similar model was performed. The fitting of the utilized model was more accurate because of the incorporation of the environmental parameters into it. Finally, the proposed model was utilized in order to predict the capillary water uptake under hypothetical extreme weather real-case scenarios. It was found that the proposed model can successfully predict the capillary water uptake under different real-case environmental conditions. The applicability of this semi-empirical model, using parameters with physical meaning, could make it suitable for use in building simulators. This model can contribute to risk assessment tools, dealing with various challenges related to climate change and its effect upon built environment.

Strongly maximal intersection-complete neural codes on grids are convex

The brain encodes spatial structure through a combinatorial code of neural activity. Experiments suggest such codes correspond to convex areas of the subject’s environment. We present an intrinsic condition that implies a neural code may correspond to a collection of convex sets and give a bound on the minimal dimension underlying such a realization.

High-resolution mapping of DNA polymerase fidelity using nucleotide imbalances and next-generation sequencing.

DNA polymerase fidelity is affected by both intrinsic properties and environmental conditions. Current strategies for measuring DNA polymerase error rate in vitro are constrained by low error subtype sensitivity, poor scalability, and lack of flexibility in types of sequence contexts that can be tested. We have developed the Magnification via Nucleotide Imbalance Fidelity (MagNIFi) assay, a scalable next-generation sequencing assay that uses a biased deoxynucleotide pool to quantitatively shift error rates into a range where errors are frequent and hence measurement is robust, while still allowing for accurate mapping to error rates under typical conditions. This assay is compatible with a wide range of fidelity-modulating conditions, and enables high-throughput analysis of sequence context effects on base substitution and single nucleotide deletion fidelity using a built-in template library. We validate this assay by comparing to previously established fidelity metrics, and use it to investigate neighboring sequence-mediated effects on fidelity for several DNA polymerases. Through these demonstrations, we establish the MagNIFi assay for robust, high-throughput analysis of DNA polymerase fidelity.

Dual-triggered oxygen self-supply black phosphorus nanosystem for enhanced photodynamic therapy

Nonspecific distribution of photosensitizer and the intrinsic hypoxic condition in the tumor microenvironment are two key factors limiting the efficacy of O2-dependent photodynamic therapy (PDT). Herein, a dual-triggered oxygen self-supported nanosystem using black phosphorus nanosheet (BPNS) as both photosensitizer and nanocarrier was developed to enhance PDT for tumors within hypoxic microenvironment. The BPNS platform was functionalized with folate and a blocker DNA duplex of 5′-Cy5-aptamer-heme/3′-heme labeled oligonucleotides. The resulting heme dimer could passivate its peroxidase activity. After specific recognition of aptamer-target, the quenched fluorescence is “turned” on by cellular adenosine triphosphate. The passivated nanosystem then activates the catalytic function towards excessive intracellular H2O2 to generate O2 essential to sustain BPNS-mediated PDT, leading to 8.7-fold and 7.5-fold increase of PDT efficacy in treating the hypoxic cell and tumor, respectively. Therefore, the dual-triggered oxygen self-supply nanosystem not only exerts tumor microenvironment-associated stimulus for enhanced PDT but also surmounts hypoxia-associated therapy resistance.

Effect of pH and salts on microstructure and viscoelastic properties of lemon peel acid insoluble fiber suspensions upon high pressure homogenization

In the present paper the effect of pH and salts on microstructural and viscoelastic properties of lemon peel acid insoluble fiber residue (AR) suspensions upon mild and intense shearing was investigated. To this aim, AR suspensions were adjusted to a pH of 2.5 (as is), 4.5, 5.5, 7 or 10 prior to or after high pressure homogenization (HPH) at 20 MPa (high shearing), with or without blending (low shearing). Furthermore, the effect of salts was investigated by addition of NaCl or CaCl2 to the AR suspensions upon blending and HPH. Microstructural characterization of the AR suspensions, was performed through microscopic visualization and determination of the particle size distribution by laser diffraction, whereas viscoelastic properties were determined by rheological analysis.Regardless of the pH conditions, blending prior to HPH was essential to obtain optimally functionalized AR suspensions. Furthermore, the effect of the sequence of blending and pH adjustment was negligible, whereas pH adjustment played a crucial role prior to HPH. In particular, increasing the pH above its intrinsic condition (pH 2.5) assisted the functionalization of AR suspensions by HPH, improving its viscoelastic properties. Contrarily, high salt concentrations negatively influenced the functionalization of AR suspensions. This effect of pH and salts was attributed to changes in electrostatic forces between AR fibers due to the presence of negative charged residual pectin polymers, favoring fiber separation (upon HPH) and increasing its hydration potential. On the other hand, high salt concentrations will shield AR fiber charges, thereby reducing the viscoelastic properties of the fiber suspensions.

Adaptive fractional integral terminal sliding mode power control of UPFC in DFIG wind farm penetrated multimachine power system

With an aim to improve the transient stability of a DFIG wind farm penetrated multimachine power system (MPN), an adaptive fractional integral terminal sliding mode power control (AFITSMPC) strategy has been proposed for the unified power flow controller (UPFC), which is compensating the MPN. The proposed AFITSMPC controls the dq- axis series injected voltage, which controls the admittance model (AM) of the UPFC. As a result the power output of the DFIG stabilizes which helps in maintaining the equilibrium between the electrical and mechanical power of the nearby generators. Subsequently the rotor angular deviation of the respective generators gets recovered, which significantly stabilizes the MPN. The proposed AFITSMPC for the admittance model of the UPFC has been validated in a DFIG wind farm penetrated 2 area 4 machine power system in the MATLAB environment. The robustness and efficacy of the proposed control strategy of the UPFC, in contrast to the conventional PI control is vindicated under a number of intrinsic operating conditions, and the results analyzed are satisfactory.

Manifestation of octane rating, fuel sensitivity, and composition effects for gasoline surrogates under advanced compression ignition conditions

Substantial research effort has been spent on the development of advanced compression ignition (ACI) engine combustion strategies over the past decades, including homogeneous charge compression ignition (HCCI), reactivity controlled compression ignition (RCCI), and gasoline direct-injection compression-ignition (GDCI), etc. The behavior of gasoline-type fuels under compression ignition conditions has subsequently attracted extensive experimental and kinetic modeling interest. On the other hand, towards the development of future transportation fuels and engines, the evaluation of general fuel properties, instead of endless testing of specific fuels, should be the future research focus. In this study, the individual roles of the research and motor octane numbers (i.e., RON and MON) and fuel sensitivity (S) in characterizing the ignition performance of gasoline surrogates have been systematically investigated under a typical ACI engine condition using well-validated surrogate and kinetic models. The crank angle corresponding to 50% total heat release (CA50) was utilized as an indicator of the overall fuel reactivity, and iso-contours of CA50 were mapped out in the full engine operating domain characterized by the temperature and pressure at intake valve closing (IVC). By comparing the ignition performance of toluene primary reference fuel blends (TPRF) with the same RON, MON or S values, the distinctive effects and dominant ACI operating conditions of these fuel properties are clearly demonstrated. The role of equivalence ratio is also discussed by comparing the intrinsic stoichiometric condition of the standard octane rating tests and the lean mixture conditions required by ACI operation. The results show that octane sensitivity manifests itself in the high pressure low temperature operating regime for fuels with identical RON or MON, through different low temperature reactivities and heat release rates, while in low pressure high temperature conditions, combustion phasing is less sensitive to all fuel properties, including RON, MON and S. TPRFs with the same sensitivity show the largest variation of CA50 in the intermediate operating conditions, where the thermodynamic traces pass primarily through the ignition delay regime characterized by negative-temperature coefficient (NTC) behavior. Finally, by comparing the combustion phasing of five different gasoline surrogates with nearly identical RON and MON, potential compositional effects for gasoline fuels under ACI condition are further discussed via kinetic modeling. This study also demonstrates that the controlling fuel properties of gasoline-like fuels depend on ACI operating conditions (pressure and temperature trajectory), which should be carefully considered when constructing fuel metrics and comparing experimental results of ACI engines.

The importance of intrinsic traits, environment and human activities in modulating stress levels in a wild ungulate

Identifying the ecological and anthropogenic processes that affect wildlife physiology, and that may operate as chronic stressors, is of prime importance to implementing appropriate management and conservation strategies. Although advances have been made in understanding the physiological ecology of wild ungulates, little is known of how multiple intrinsic and ecological factors work, either independently or synergistically, to modulate their stress responses. By using faecal glucocorticoid metabolites (FGM) as indicators of stress, a set of environmental and human determinants affecting the stress physiology of wild red deer (Cervus elaphus) was examined in the Mediterranean ecosystems of south-western Europe, where this species is subjected to contrasting weather regimes and hunting management systems. Variation-partitioning techniques were also used to estimate the comparative influence of factors related to an individual’s intrinsic characteristics, environmental conditions and management practices in shaping physiological stress levels. Our results showed that factors related to hunting management were the main drivers of FGM variation in red deer, followed by those related to the environmental conditions and individuals’ traits, and their effects were closely associated to spatio-temporal variability. Holding massive hunting events involving the use of hounds, as well as high population densities, were related to more long-term stress levels in the populations studied. Evidence was also found that supplementary feeding practices may mitigate the negative effects of reduced food availability in overabundant deer populations. Weather conditions were also significant factors explaining variation in stress levels; accumulated rainfall and an increase in ambient temperatures during the coldest months were associated with a decrease in stress hormone levels. No differences in hormonal concentrations were found between males and females, but higher levels of hormone metabolites were detected in younger animals in both sexes. Our findings provide an integrated perspective of how multiple factors impact on stress physiology in large wild herbivores and highlight the importance of considering management practices, as well as spatio-temporal variation, when assessing stress-inducing factors in wild populations. Given the implications of this study regarding the impact of human activities on physiological stress levels in wild animals, it could be an important basis to support wildlife management decisions.

Child Living Conditions and Orphanhood Status in Uganda: an Extension of the Application of the Intrinsic Value Approach to Child Poverty Measurement

Association between orphanhood status and a child’s development outcomes is contested among authors. The contestation mainly focusses on the differences between orphans and non-orphans based on single indicators. However, focusing on single indicators such as education does not account for the multidimensional nature of living conditions of children as per here and now. In this study Child Living Conditions which take on many dimensions are computed using the intrinsic value approach. We tested the hypothesis that the average living conditions of orphans were less than the average living conditions of non-orphans in Uganda in 2011. Uganda Demographic and Health Survey data for 2011 was analysed using Multilevel mixed effects regression to achieve the objectives. Although some differences between orphans and non-orphans were observed, the margin was small. Notably the average conditions of children who lived in female headed households was less than for children in male headed households, less for rural than urban children and less for children in distant regions than for children in Kampala and the central region. The major factors which strongly associated with the variation in child living conditions were household headship, place of residence and regional differences. Thus rather than emphasizing the association between orphanhood or other child characteristics, and child living conditions, the conditions that perpetuate the low intrinsic value conditions for all children should be targeted

Experimental assessment of the shield-to-salt-fog properties of basalt and glass fiber reinforced composites in cork core sandwich panels applications

Abstract In this paper, the effect of salt-fog exposition on the mechanical behavior of sandwich panels having cork agglomerate core was investigated. In particular, the aim of this research work is to assess the shield function of unidirectional basalt and E-glass reinforced polymer on the aging and failure mechanism of the core when such class of material are destined to operate in hostile environments (e.g., marine environment). To do this, the manufactured sandwich panels were exposed up to 60 days to salt-fog environment, according to ASTM B 117 standard. Unaged and aged specimens were analyzed through three point bending tests after aging time of 10, 25 and 60 days. Digital Image Correlation (DIC) was carried out to perform a strain field analysis of the longitudinal cross-sections. The differences in the mechanical behavior of the synergistic cooperation of the cork core with basalt and glass fiber were highlighted thorough this technique. Moreover, the failure mechanisms related to each combinations for different aging times were described. The experimental results showed that, the intrinsic conditions of the composites (e.g., presence of defects, poor fiber-matrix adhesion), that are strictly linked to the fiber-matrix compatibility and to the impregnation quality, may induce to differences in the local mechanical behavior of the sandwich panels and to a faster aging process of the cork core in the case of basalt fiber skinned sandwich, especially in the first phases of the exposition.

Horrendous-Difference Disabilities, Resurrected Saints, and the Beatific Vision: A Theodicy

Marilyn Adams rightly pointed out that there are many kinds of evil, some of which are horrendous. I claim that one species of horrendous evil is what I call horrendous-difference disabilities. I distinguish two subspecies of horrendous-difference disabilities based in part on the temporal relation between one’s rational moral wishing for a certain human function F and its being thwarted by intrinsic and extrinsic conditions. Next, I offer a theodicy for each subspecies of horrendous-difference disability. Although I appeal to some claims made by Marilyn Adams for this theodicy, I reject one particular claim. I deny that one must be aware that one participates in a horrendous evil when the horrific event occurs. To develop this point and its relevance for a theodicy for horrendous-difference disabilities, I engage with Andrew Chignell’s work on infant suffering. In doing so, I show that what partly motivates the claim is a time-bias, i.e., near-bias. By rejecting this time-bias, I show how it is possible, given post-mortem life, for persons with profound cognitive disabilities to participate in horrendous evils and how these might be defeated by God.

Parametric Study on Intrinsic Reaction for Straight Run Heavy Naphtha Hydrodesulfurization over CoMo/Al2O3 Catalyst

The present study aimed to investigate the intrinsic reaction of hydrodesulfurization (HDS) for a real Straight Run Heavy Naphtha (SRHN) over CoMo-S/Al2O3 catalyst in a fixed- bed reactor. Influence of the process parameters on sulfur removal was investigated by regulating the temperature (T = 320-380 oC), pressure (P = 20 to 35 bar), weight hour space velocity (WHSV = 2.5 to 5.0 h-1) and catalyst average particle size (dp =361 to 3950 μm). Mears and Weisz-Prater criteria were estimated and utilized to validate the intrinsic reaction condition. Operating variables were optimized at (T = 360 oC, P = 30 bars, WHSV = 2.5 h-1, dp= 361 μm) to obtain an optimum sulfur removal of 93.4% under intrinsic reaction conditions. Experimental results showed that % activity of sulfur removal increases to 93.4% as temperature increased to 360oC but it reduces to 90.3% as space velocity increased to 5.0 h-1. Kinetic parameters of the intrinsic reaction rate were estimated and compared with published data. Long-time test was performed on the sulfided catalyst to investigate its activity.

Hydrogen-surfactant-assisted coherent growth of GaN on ZnO substrate

Heterostructures of wurtzite based devices have attracted great research interest because of the tremendous success of GaN in light emitting diodes (LED) industry. High-quality GaN thin films on inexpensive and lattice matched ZnO substrates are both commercially and technologically desirable. Intrinsic wetting conditions, however, forbid such heterostructures as the energy of ZnO polar surfaces is much lower than that of GaN polar surfaces, resulting in 3D growth mode and poor crystal quality. Based on first-principles calculations, we propose the use of surfactant hydrogen to dramatically alter the growth mode of the heterostructures. Stable H-involved surface configurations and interfaces are investigated with the help of our newly developed modelling techniques. The temperature and chemical potential dependence of our proposed strategy, which is critical in experiments, is predicted by applying the experimental Gibbs free energy of ${\mathrm{H}}_{2}$. Our thermodynamic wetting condition analysis is a crucial step for the growth of GaN on ZnO, and we find that introducing H will not degrade the stability of ZnO substrate. This approach will allow the growth of high-quality GaN thin films on ZnO substrates. We believe that our new strategy may reduce the manufactory cost, improve the crystal quality, and improve the efficiency of GaN-based devices.